• Journal of Microbiology
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• 제37권2호
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• pp.90-96
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• 1999

The core protein of the hepatitis C virus (HCV) is a multifunctional protein. The HCV core protein was reported to regulate cellular gene expression and transform primary rat embryo fibroblast cells. However, the role of the core protein in the pathogenesis of HCV-associated liver diseases is not well understood. To investigate the functional role of the core protein in cytophathogenicity, we have constructed stable expression systems of full length or truncated HCV core protein lacking the C-terminal hyderophobic domains and established HepG2 cell clones constitutively expressing the core protein. The full length core protein was localized in the cytoplasm and the C-terminal truncated core protein was localized in the nucleus. HepG2 cells expressing nuclear, truncated core protein showed elevated cell death during cultivation compared to untransfected cells and full length core-expressing cells. In the treatment with bleomycin, both cell clones expressing full length or truncated core protein appeared to be more sensitive to blemoycin than the parental HepG2 cells. These results suggest that the core protein may play a role in HCV pathogenesis promoting apoptotic cell death of infected cells.

• Corrosion Science and Technology
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• 제14권2호
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• pp.64-75
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• 2015

Single $TiO_2$ coating prepared by sol-gel process usually experiences cracks in coating layer. In order to prevent cracks, an inorganic-organic hybrid $TiO_2-SiO_2$ coating was synthesized by combining precursors with an organic functional group. Five different coatings with various ratios of (1:8, 1:4, 1:1, 1:0.25 and 1:0.125) titanium alkoxide (TBOT, Tetrabutylorthotitanate) to organo-alkoxysilane (MAPTS, ${\gamma}$-Methacryloxy propyltrimethoxysilane) on carbon steel substrate were made by sol-gel dip coating. The prepared coatings were analyzed to study the coating properties (surface crack, thickness, composition) by scanning electron microscope (SEM), focused ion beam (FIB), and Fourier transform infrared spectroscopy (FT-IR). Potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were also performed to evaluate the corrosion characteristics of the coatings. Crack free $TiO_2-SiO_2$ hybrid coatings were prepared with the optimization of the ratio of TBOT to MAPTS. The corrosion rates were significantly decreased in the coatings for the optimized precursor ratio without cracks.

• Carbon letters
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• 제12권3호
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• pp.167-170
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• 2011

Petroleum pitch-based activated carbons (ACs) were obtained in this work from a combination of pretreatment with different amounts of potassium permanganate ($KMnO_4$) and chemical activation with potassium hydroxide. The surface characteristics of the pitch after the $KMnO_4$ pretreatment were characterized by means of Fourier transform infrared spectroscopy (FT-IR). The structural characteristics of the pitch after the $KMnO_4$ pretreatment were determined by means of X-ray diffraction. The influence of the $KMnO_4$ treatment on the textural properties of the petroleum pitch-based ACs was investigated by means of $N_2$/77K adsorption isotherms. The investigation also involved the use of the Brunauer-Emmett-Teller equation and the Dubinin-Radushkevich method. The FT-IR results show that the pretreatment promotes the formation of surface oxygen functionalities and leads to an increase of the interplanar distance ($d_{002}$) of the functional groups induced between carbon layers. Moreover, the specific surface area of the pitch-based ACs increases in proportion to the amount of $KMnO_4$ pretreatment and reaches its highest value of 2334 $m^2$/g with 2 g of $KMnO_4$ because the surface oxygen groups of the pitch act as an active site during chemical activation.

• Carbon letters
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• 제12권3호
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• pp.138-142
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• 2011

Poly(vinyl alcohol) (PVA) composites with various graphite oxide (GO) contents (0 to 10 wt%) were prepared by sonicating the mixture of PVA and GO, followed by crosslinking with glutaraldehyde. GO was pre-treated with oxyfluorination ($O_2:F_2$ = 8:2) in order to modify the surface of GO to allow it to carry hydrophilic functional groups. PVA/GO composite hydrogels were characterized by scanning electron microscopy and Fourier-transform infrared spectrometer (FT-IR). The morphology of the PVA/GO composite hydrogels and the variations in soluble gel portion were investigated under various GO contents and UV irradiation doses. The variation in the chemical structure of photo degraded PVA/GO composite hydrogels was studied by FT-IR. The photochemical stability of PVA/GO composite hydrogels under UV irradiation was found to improve noticeably with increasing content of uniformly dispersed GO.

• 한국전자거래학회지
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• 제1권2호
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• pp.49-76
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• 1996

An industrial process is a sequence of steps intended to perform a useful task in an industrial organization, and can be described using a model or a representation framework such as function model, information model, process flow model, etc. Many researchers, however, claim that, all those models from different perspectives are required to describe complex systems such as CIMS. Thus these perspectives should be put together to build an optimal system. And the need for interconnection or transformation among different view points has arisen for effective communications between system developers and easy propogation of local changes in a model. But it seems to be difficult to integrate such models into a unified framework as they describe different aspects of the system on different purposes. This study is an attempt to interconnect these different perspectives, and thereby to support conceptual design of systems in a more effective manner. A methodology to transform the IDEFO functional model into a process flow model is proposed. The validity of the proposed approach is tested by developing a prototye of a computer-assisted design system on the operation processes of FMS installed at Seoul National University - Automation and Systems Research Institute.

• Journal of Information Processing Systems
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• 제12권1호
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• pp.1-34
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• 2016

Gene identification is at the center of genomic studies. Although the first phase of the Encyclopedia of DNA Elements (ENCODE) project has been claimed to be complete, the annotation of the functional elements is far from being so. Computational methods in gene identification continue to play important roles in this area and other relevant issues. So far, a lot of work has been performed on this area, and a plethora of computational methods and avenues have been developed. Many review papers have summarized these methods and other related work. However, most of them focus on the methodologies from a particular aspect or perspective. Different from these existing bodies of research, this paper aims to comprehensively summarize the mainstream computational methods in gene identification and tries to provide a short but concise technical reference for future studies. Moreover, this review sheds light on the emerging trends and cutting-edge techniques that are believed to be capable of leading the research on this field in the future.

• Carbon letters
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• 제14권1호
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• pp.14-21
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• 2013

Physically and chemically activated carbons (ACs) exhibited high adsorption capacities for organic and inorganic pollutants compared with other adsorbents due to their expanded surface areas and wide pore volume distribution. In this work, seven steam-ACs with different burn-off have been prepared from cotton stalks. The textural properties of these sorbents were determined using nitrogen adsorption at $-196^{\circ}C$. The chemistry of the surface of the present sorbents was characterized by determining the surface functional C-O groups using Fourier transform infrared spectroscopy, surface pH, $pH_{pzc}$, and Boehm's acid-base neutralization method. The textural properties and the morphology of the sorbent surface depend on the percentage of burn-off. The surface acidity and surface basicity are related to the burn-off percentage. A theoretical model was developed to find a mathematical expression that relates the % burn-off to ash content, surface area, and mean pore radius. Also, the chemistry of the carbon surface is related to the % burn-off. A mathematical expression was proposed where % burn-off was taken as an independent factor and the other variable as a dependent factor. This expression allows the choice of the value of % burn-off with required steam-AC properties.

• The Journal of Advanced Prosthodontics
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• 제8권3호
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• pp.187-193
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• 2016

PURPOSE. This pilot study was to find the influence of complete denture on the brain activity and cognitive function of edentulous patients measured through Electroencephalogram (EEG) signals. MATERIALS AND METHODS. The study recruited 20 patients aged from 50 to 60 years requiring complete dentures with inclusion and exclusion criteria. The brain function and cognitive function were analyzed with a mental state questionnaire and a 15-minute analysis of power spectral density of EEG alpha waves. The analysis included edentulous phase and post denture insertion adaptive phase, each done before and after chewing. The results obtained were statistically evaluated. RESULTS. Power Spectral Density (PSD) values increased from edentulous phase to post denture insertion adaption phase. The data were grouped as edentulous phase before chewing (EEG p1-0.0064), edentulous phase after chewing (EEG p2-0.0073), post denture insertion adaptive phase before chewing (EEG p3-0.0077), and post denture insertion adaptive phase after chewing (EEG p4-0.0096). The acquired values were statistically analyzed using paired t-test, which showed statistically significant results (P<.05). CONCLUSION. This pilot study showed functional improvement in brain function of edentulous patients with complete dentures rehabilitation.

• 한국가구학회지
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• 제20권4호
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• pp.388-403
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• 2009

Nature is suiting to the objective of oneself, structurally safe and functional. It continues to transform itself into various forms and has aesthetic beauty. By analyzing how nature's organic property has been expressed in different cases of furniture design, which has objective purpose, this research presents designing pathway to induce nature's organic oder into the furniture design. Simile expression type clearly shows its form through exposing the natural material that it is made out of. Visually, esthetic beauty can be emphasized and mentally it can provide pleasantness. Metaphorical expression type only hints the original material that was used to reproduce. Under the same condition it can have subjective perception and it needs to be used suitably at the right place and time. Abstract expression type it might be hard to recognize the original material visually since it went through many transformation in expression, however it can stage extreme and mysterious atmosphere. Furniture designs employing these three types can have functionality as well as decorative and serve variety of change in the existing uniformed interior space, and it can also satisfy individual's need with practicality and provide aesthetic beauty.

• Carbon letters
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• 제12권1호
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• pp.1-7
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• 2011

In the present study, the removal of Pb (II) ions on oxidized activated carbons (ACs) was investigated. ACs were derived from activation of indigenous cotton stalks waste with potassium hydroxide (KOH) in two-stage process. The KOH-ACs were subjected to liquid-phase oxidation with hot $HNO_3$ and one untreated sample was included for comparison. The obtained carbons were characterized by Fourier transform infrared (FTIR), slurry pH and $N_2$-adsorption at 77 K, respectively. Adsorption capacity of Pb (II) ions on the resultant carbons was determined by batch equilibrium experiments. The experimental results indicated that the oxidation with nitric acid was associated with a significant increase in mass of yield as well as a remarkable reduction in internal porosity as compared to the untreated carbon. The AC-800N revealed higher adsorption capacity than that of AC-800, although the former sample exhibited low surface area and micropore volume. It was observed that the adsorption capacity enhancement attributed to pore widening, the generation of oxygen functional groups and potassium containing compounds leading to cation-exchange on the carbon surface. These results show that the oxidized carbons represented prospective adsorbents for enhancing the removal of heavy metals from wastewater.